It’s available in 10 mg and 20 mg tablets. Cialis Daily tadalafil : This low-dose Cialis works by increasing blood flow to the penis over time, making it easier to have an erection when aroused. Make sure to get an estimate of when you can expect your prescription in the mail. Privacy: Confirm that your personal data and payment details are confidential. At the same time, the brain tells other vessels near the penis to tighten up, to keep blood in this sponge tissue — and this is what makes an erection last. It works for up to 36 hours. But plenty of men willingly pay more for Viagra because they like to use the name brand.Compare prices and print coupons for Sildenafil (Generic Revatio and Viagra) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $Missing: usa. Best Low Cost: GoodRx Fastest Delivery: Blink Health: Sesame Sign Up Now Key Specs Cost: Consultation prices vary based on the prescriber; $5 generic prescriptions Medical Consultation Required: Yes Medications Prescribed: Viagra, Cialis, sildenafil, tadalafil Generic offered: Yes Why We Chose ItMissing: usa. In the United States, sildenafil for ED or PH requires a prescription. The United Kingdom allows for over-the-counter (OTC) sales of the drug, in part to discourage the market for fake sildenafil.